Ingredients:

  • 250g all-purpose flour
  • 350g granulated sugar
  • 75g Dutch-process cocoa powder
  • 2 tsp baking powder
  • 1.5 tsp baking soda
  • 1.5 tsp kosher salt
  • 2 large eggs, room temperature
  • 240ml whole milk
  • 120ml vegetable oil
  • 2 tsp vanilla extract
  • 240ml boiling water or hot coffee
  • 45g all-purpose flour (for filling)
  • 240ml whole milk (for filling)
  • 225g unsalted butter, softened
  • 150g granulated sugar (for filling)
  • 250g dark chocolate (60% cacao), finely chopped
  • 240ml heavy cream
  • 1 tbsp light corn syrup

Instructions:

  1. Preheat oven to 350°F (175°C). Grease two 9-inch round cake pans and line the bottoms with parchment paper.
  2. Whisk the 250g flour, 350g sugar, 75g cocoa, baking powder, baking soda, and salt until no lumps remain.
  3. Add the 2 large eggs, 240ml milk, 120ml oil, and vanilla. Mix on medium speed until the batter is smooth and glossy.
  4. Pour in the 240ml boiling water or coffee. Mix by hand until the batter is very thin and watery.
  5. Bake at 350°F (180°C) for 35 minutes until a toothpick comes out with a few moist crumbs.
  6. Whisk 45g flour and 240ml milk in a saucepan over medium heat until it thickens into a heavy paste.
  7. Cool this roux completely. Cream the 225g butter and 150g sugar until incredibly pale and fluffy.
  8. Add the cooled flour paste one tablespoon at a time to the butter until it resembles whipped cream.
  9. Heat 240ml heavy cream and 1 tbsp corn syrup until it just begins to simmer.
  10. Pour over 250g chopped chocolate. Let sit for 5 minutes, then whisk until it is a liquid, obsidian mirror.
  11. Frost the cooled cake with the filling, chill for 30 minutes, then pour the ganache over the top until it drips down the sides.